The present invention refers to an electromagnetic force device arranged to provide a force. The invention also refers to a shock absorber, a scale, a sewing machine and a handling device, respectively, with such a force device.
Electric force devices are used in a plurality of various applications where there is a need of a force. The force may be utilised for moving an object along a straight or curved path in order to obtain a reciprocating movement, in order to tighten two objects towards or away from each other, etc. In such applications there is a need of force devices which are small and compact, which have a simple construction, which are cheap, which are reliable and which have a small energy consumption.
A concrete example of an application are active shock absorbers which are used in for instance motor vehicles and in the industry. By active shock absorbers are referred to such absorbers where the damping capability and the spring properties may be adjusted and adapted to various needs. U.S. Pat. No. 5,497,325 and U.S. Pat. No. 5,572,426 disclose two examples of active hydraulic shock absorbers, which have a relatively complicated constriction.
U.S. Pat. No. 3,238,397 discloses an electric machine with a reciprocating shaft, wherein a reciprocating movement is obtained by means of electromagnets arranged around the shaft.